Scanning Tunnelling Microscopy (STM) is a powerful experimental technique in surface science. It combines atomic resolution imaging with the opportunity to perform nanoscale manipulations. Additionally, STM enable the mapping of the density of states of materials. Here we report investigations on aza-BODIPY adsorbed on metal surfaces with a low-temperature STM/AFM-System. Aza-BODIPY (e.g. 1,3,5,7-tetraphenyl-8-azadipyromethene) are a class of organic fluorescent dyes characterised by the same molecular core region consisting of two pyrroles connected by a boronfluorine complex and a nitrogen atom. These molecules exhibit strong chemical stability and highly tuneable, sharp absorption wavelength. Aza-BODIPY has previously been used for immunostaining and photodynamic therapy during the last few years. Recently, electron donor materials for organic photovoltaics (OPVs) has emerged as another field of application, due to aza-BODIPYs strong infrared absorption. In this work we investigated single aza-BODIPY molecules adsorbed on Ag(110) and Au(111) by STM at 77 K and 5 K. We verified the adsorption configuration and geometry and found it to be in qualitative agreement with theoretical simulations. In addition we conducted spectroscopy measurements to determine the electronic structure of the molecule on the surface.